From: Aditya Gupta <[email protected]> While the first kernel boots, it registers memory regions for fadump such as: * CPU state data (has to be populated by the platform) * HPTE state data (has to be populated by the platform) * Real Mode Regions (platform should copy it to requested destination addresses) * OS defined regions (such as parameter save area)
Platform is also expected to modify the 'bytes_dumped' to the length of data preserved/copied by platform (ideally same as the source length passed by kernel). The kernel passes source address and length for the memory regions, and a destination address to where the memory is to be copied. Implement the preserving/copying of the Real Mode Regions and the Parameter Save Area in QEMU Pseries The regions are copied in chunks instead of copying all at once. Signed-off-by: Aditya Gupta <[email protected]> Reviewed-by: Sourabh Jain <[email protected]> Tested-by: Shivang Upadhyay <[email protected]> Link: https://lore.kernel.org/qemu-devel/[email protected] Signed-off-by: Harsh Prateek Bora <[email protected]> --- include/hw/ppc/spapr_fadump.h | 18 ++++ hw/ppc/spapr_fadump.c | 183 +++++++++++++++++++++++++++++++++- 2 files changed, 196 insertions(+), 5 deletions(-) diff --git a/include/hw/ppc/spapr_fadump.h b/include/hw/ppc/spapr_fadump.h index 1cb90c9d63..71be2ad92c 100644 --- a/include/hw/ppc/spapr_fadump.h +++ b/include/hw/ppc/spapr_fadump.h @@ -16,11 +16,29 @@ #define FADUMP_VERSION 1 +/* Firmware provided dump sections */ +#define FADUMP_CPU_STATE_DATA 0x0001 +#define FADUMP_HPTE_REGION 0x0002 +#define FADUMP_REAL_MODE_REGION 0x0011 + +/* OS defined sections */ +#define FADUMP_PARAM_AREA 0x0100 + +/* Dump request flag */ +#define FADUMP_REQUEST_FLAG 0x00000001 + /* Dump status flags */ #define FADUMP_STATUS_DUMP_PERFORMED 0x8000 #define FADUMP_STATUS_DUMP_TRIGGERED 0x4000 #define FADUMP_STATUS_DUMP_ERROR 0x2000 +/* Region dump error flags */ +#define FADUMP_ERROR_INVALID_DATA_TYPE 0x8000 +#define FADUMP_ERROR_INVALID_SOURCE_ADDR 0x4000 +#define FADUMP_ERROR_LENGTH_EXCEEDS_SOURCE 0x2000 +#define FADUMP_ERROR_INVALID_DEST_ADDR 0x1000 +#define FAUDMP_ERROR_DEST_TOO_SMALL 0x0800 + /* * The Firmware Assisted Dump Memory structure supports a maximum of 10 sections * in the dump memory structure. Presently, three sections are used for diff --git a/hw/ppc/spapr_fadump.c b/hw/ppc/spapr_fadump.c index 53e5c12c76..5068a9d83d 100644 --- a/hw/ppc/spapr_fadump.c +++ b/hw/ppc/spapr_fadump.c @@ -7,7 +7,9 @@ #include "qemu/osdep.h" #include "qemu/log.h" #include "hw/ppc/spapr.h" +#include "qemu/units.h" #include "system/cpus.h" +#include <math.h> /* * Handle the "FADUMP_CMD_REGISTER" command in 'ibm,configure-kernel-dump' @@ -123,14 +125,185 @@ uint32_t do_fadump_register(SpaprMachineState *spapr, target_ulong args) return RTAS_OUT_SUCCESS; } +/* + * Copy the source region of given fadump section, to the destination + * address mentioned in the region + * + * Also set the region's error flag, if the copy fails due to non-existent + * address (MEMTX_DECODE_ERROR) or permission issues (MEMTX_ACCESS_ERROR) + * + * Returns true if successful copy + * + * Returns false in case of any other error, being treated as hardware + * error for fadump purposes + */ +static bool do_preserve_region(FadumpSection *region) +{ + AddressSpace *default_as = &address_space_memory; + MemTxResult io_result; + MemTxAttrs attrs; + uint64_t src_addr, src_len, dest_addr; + uint64_t num_chunks; + g_autofree void *copy_buffer = NULL; + + src_addr = be64_to_cpu(region->source_address); + src_len = be64_to_cpu(region->source_len); + dest_addr = be64_to_cpu(region->destination_address); + + /* Mark the memory transaction as privileged memory access */ + attrs.user = 0; + attrs.memory = 1; + + /* + * Optimisation: Skip copy if source and destination are same + * (eg. param area) + */ + if (src_addr == dest_addr) { + region->bytes_dumped = cpu_to_be64(src_len); + return true; + } + +#define FADUMP_CHUNK_SIZE ((size_t)(32 * MiB)) + copy_buffer = g_try_malloc(FADUMP_CHUNK_SIZE); + if (copy_buffer == NULL) { + qemu_log_mask(LOG_GUEST_ERROR, + "FADump: Failed allocating memory (size: %zu) for copying" + " reserved memory regions\n", FADUMP_CHUNK_SIZE); + } + + num_chunks = ceil((src_len * 1.0f) / FADUMP_CHUNK_SIZE); + for (uint64_t chunk_id = 0; chunk_id < num_chunks; ++chunk_id) { + /* Take minimum of bytes left to copy, and chunk size */ + uint64_t copy_len = MIN( + src_len - (chunk_id * FADUMP_CHUNK_SIZE), + FADUMP_CHUNK_SIZE + ); + + /* Copy the source region to destination */ + io_result = address_space_read(default_as, src_addr, attrs, + copy_buffer, copy_len); + if ((io_result & MEMTX_DECODE_ERROR) || + (io_result & MEMTX_ACCESS_ERROR)) { + qemu_log_mask(LOG_GUEST_ERROR, + "FADump: Failed to decode/access address in section: %d\n", + region->source_data_type); + + /* + * Invalid source address is not an hardware error, instead + * wrong parameter from the kernel. + * Return true to let caller know to continue reading other + * sections + */ + region->error_flags = FADUMP_ERROR_INVALID_SOURCE_ADDR; + region->bytes_dumped = 0; + return true; + } else if (io_result != MEMTX_OK) { + qemu_log_mask(LOG_GUEST_ERROR, + "FADump: Failed to read source region in section: %d\n", + region->source_data_type); + + return false; + } + + io_result = address_space_write(default_as, dest_addr, attrs, + copy_buffer, copy_len); + if ((io_result & MEMTX_DECODE_ERROR) || + (io_result & MEMTX_ACCESS_ERROR)) { + qemu_log_mask(LOG_GUEST_ERROR, + "FADump: Failed to decode/access address in section: %d\n", + region->source_data_type); + + /* + * Invalid destination address is not an hardware error, + * instead wrong parameter from the kernel. + * Return true to let caller know to continue reading other + * sections + */ + region->error_flags = FADUMP_ERROR_INVALID_DEST_ADDR; + region->bytes_dumped = 0; + return true; + } else if (io_result != MEMTX_OK) { + qemu_log_mask(LOG_GUEST_ERROR, + "FADump: Failed to write destination in section: %d\n", + region->source_data_type); + + return false; + } + + src_addr += FADUMP_CHUNK_SIZE; + dest_addr += FADUMP_CHUNK_SIZE; + } +#undef FADUMP_CHUNK_SIZE + + /* + * Considering address_space_write would have copied the + * complete region + */ + region->bytes_dumped = cpu_to_be64(src_len); + return true; +} + /* Preserve the memory locations registered for fadump */ -static bool fadump_preserve_mem(void) +static bool fadump_preserve_mem(SpaprMachineState *spapr) { + FadumpMemStruct *fdm = &spapr->registered_fdm; + uint16_t dump_num_sections, data_type; + + assert(spapr->fadump_registered); + /* - * TODO: Implement preserving memory regions requested during fadump - * registration + * Handle all sections + * + * CPU State Data and HPTE regions are handled in their own cases + * + * RMR regions and any custom OS reserved regions such as parameter + * save area, are handled by simply copying the source region to + * destination address */ - return false; + dump_num_sections = be16_to_cpu(fdm->header.dump_num_sections); + for (int i = 0; i < dump_num_sections; ++i) { + data_type = be16_to_cpu(fdm->rgn[i].source_data_type); + + /* Reset error_flags & bytes_dumped for now */ + fdm->rgn[i].error_flags = 0; + fdm->rgn[i].bytes_dumped = 0; + + /* If kernel did not request for the memory region, then skip it */ + if (be32_to_cpu(fdm->rgn[i].request_flag) != FADUMP_REQUEST_FLAG) { + qemu_log_mask(LOG_UNIMP, + "FADump: Skipping copying region as not requested\n"); + continue; + } + + switch (data_type) { + case FADUMP_CPU_STATE_DATA: + /* TODO: Add CPU state data */ + break; + case FADUMP_HPTE_REGION: + /* TODO: Add hpte state data */ + break; + case FADUMP_REAL_MODE_REGION: + case FADUMP_PARAM_AREA: + /* Copy the memory region from region's source to its destination */ + if (!do_preserve_region(&fdm->rgn[i])) { + qemu_log_mask(LOG_GUEST_ERROR, + "FADump: Failed to preserve dump section: %d\n", + be16_to_cpu(fdm->rgn[i].source_data_type)); + fdm->header.dump_status_flag |= + cpu_to_be16(FADUMP_STATUS_DUMP_ERROR); + } + + break; + default: + qemu_log_mask(LOG_GUEST_ERROR, + "FADump: Skipping unknown source data type: %d\n", data_type); + + fdm->rgn[i].error_flags = + cpu_to_be16(FADUMP_ERROR_INVALID_DATA_TYPE); + } + } + + return true; } /* @@ -151,7 +324,7 @@ void trigger_fadump_boot(SpaprMachineState *spapr, target_ulong spapr_retcode) pause_all_vcpus(); /* Preserve the memory locations registered for fadump */ - if (!fadump_preserve_mem()) { + if (!fadump_preserve_mem(spapr)) { /* Failed to preserve the registered memory regions */ rtas_st(spapr_retcode, 0, RTAS_OUT_HW_ERROR); -- 2.43.5
